package Day18;

import javafx.scene.transform.Scale;

import java.util.Scanner;

/**
 * Creat with IntelliJ IDEA
 * Description
 * User: mamba24
 * Date: 2022-10-01
 * Time: 22:26
 * To BE A Better Person-2020-3-2
 */
public class TestDemo {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int m=sc.nextInt();
        int num1=1;
        int num2=1;
        for (int i = 2; i < m; i++) {
            int temp=num2;
            num2+=num1;
            num1=temp;
        }
        System.out.println(num2);
    }
}
